The protection of crops from weeds and other vegetation which inhibit crop growth is a constantly recurring problem in agriculture. To help combat this problem, researchers in the field of synthetic chemistry have produced an extensive variety of chemicals and chemical formulations effective in the control of such unwanted growth. Chemical herbicides of many types have been disclosed in the literature and a large number are in commercial use.
In some cases, herbicidal active ingredients have been shown to be more effective in combination than when applied individually and this is referred to as “synergism.” As described in the Herbicide Handbook of the Weed Science Society of America, Ninth Edition, 2007, p. 429, “‘synergism’ [is] an interaction of two or more factors such that the effect when combined is greater than the predicted effect based on the response to each factor applied separately.” The present invention is based on the discovery that (a) aminopyralid and 2,4-D and (b) atrazine, already known individually for their herbicidal efficacy, display a synergistic effect when applied in combination.
The herbicidal compounds forming the synergistic composition of this invention are independently known in the art for their effects on plant growth.
Aminopyralid, 4-amino-3,6-dichloro-2-pyridinecarboxylic acid, is a picolinic acid or pyridine herbicide. It is described in The Pesticide Manual, Fifteenth Edition, 2009. Aminopyralid is used for long-term control of annual and perennial broadleaf weeds in grassland.
2,4-D is the common name for 2,4-dichlorophenoxyacetic acid. Its herbicidal activity is described in The Pesticide Manual, Fifteenth Edition, 2009. 2,4-D controls both annual and perennial broadleaf weeds in a variety of grassy crops.
Atrazine is the common name for 6-chloro-N-ethyl-N′-(1-methylethyl)-1,3,5-triazine-2,4-diamine. Its herbicidal activity is described in The Pesticide Manual, Fifteenth Edition, 2009. Atrazine provides pre- and post-emergence control of annual broadleaf weeds and annual grasses in maize, sorghum, sugar cane, pineapples, chemical fallow, grassland, macadamia nuts, conifers, and industrial weed control.
Tronador™ herbicide is a post-emergence herbicide containing aminopyralid at 9 grams acid equivalent per liter (g ae/L) and 2,4-D at 180 g ae/L in a soluble concentrated formulation, sold by Dow AgroSciences LLC. Tronador™ herbicide controls several broadleaf weeds in corn crops. Tronador at 1.5 L/ha is equivalent to 283.5 g ae/ha (13.5 g ae/ha aminopyralid +270 g ae/ha 2,4-D).